Process for producing zirconium sols and gels, and process for producing zirconia using the same

Abstract

A process for producing acidic boratozirconium chloride sols which comprises: reacting a zirconium compound with a boron compound in molar ratios of B/Zr of 0.3-1.2 together with a compound of a metal M other than boron, the metal M being selected from the group consisting of divalent, trivalent, tetravalent and pentavalent metals in molar ratios of M/Zr of about 0.01-1 in water in the presence of chloride ions in molar ratios of Cl/Zr of not less than about 1. The acidic boratozirconium chloride sol may be converted to basic boratozirconium sols by reacting the acidic sol with a basic carbonate compound such as ammonium carbonate. The sols, either acidic or basic, are readily gelled by contact with a dehydration solvent such as methanol or acetone. The gel is calcined at relatively low temperatures to provide zirconia which is either very pure or stabilized in varied degrees.

What is claimed is: 
     
       1. A process for gellation of zirconium ammonium carbonate sols which comprises: bringing the zirconium ammonium carbonate sol into contact with a dehydration solvent selected from the group consisting of a dialkyl ketone wherein each alkyl group has 1-3 carbons and a lower aliphatic alcohol having 1-5 carbons, the dehydration solvent containing:   (i) a compound of a metal selected from the group consisting of divalent, trivalent, tetravalent and pentavalent metals; or   (ii) boric acid or ammonium borate; or   (iii) boric acid or ammonium borate together with a compound of a metal selected from the group consisting of divalent, trivalent, tetravalent and pentavalent metals.   
     
     
       2. The process as claimed in claim 1, wherein the divalent metal is Mg, Ca, Ba, Sr, Pb, Ni, Cu, Zn or Mn; the trivalent metal is Y, Al, Fe, Ga, In, Bi, Ce or La; the tetravalent metal is Ti, Sn, Si, Ge or Te; and the pentavalent metal is V, Mo, Sb or W. 
     
     
       3. The process as claimed in claim 1, wherein the dehydration solvent is methanol, isopropanol or acetone. 
     
     
       4. A process for gellation of zirconium ammonium carbonate sols which comprises: (a) reacting the zirconium ammonium carbonate sol with boric acid or ammonium borate to provide a boratozirconium ammonium carbonate sol; and   (b) bringing the sol into contact with a dehydration solvent selected from the group consisting of a dialkyl ketone wherein each alkyl group has 1-3 carbons and a lower aliphatic alcohol having 1-5 carbons, the dehydration solvent containing:   (i) a compound of a metal selected from the group consisting of divalent, trivalent, tetravalent and pentavalent metals; or   (ii) boric acid or ammonium borate; or   (iii) boric acid or ammonium borate together with a compound of a metal selected from the group consisting of divalent, trivalent, tetravalent and pentavalent metals.   
     
     
       5. The process as claimed in claim 4, wherein the divalent metal is Mg, Ca, Ba, Sr, Pb, Ni, Cu, Zn or Mn; the trivalent metal is Y, Al, Fe, Ga, In, Bi, Ce or La; the tetravalent metal is Ti, Sn, Si, Ge or Te; and the pentavalent metal is V, Mo, Sb or W. 
     
     
       6. The process as claimed in claim 4, wherein the dehydration solvent is methanol, isopropanol or acetone. 
     
     
       7. A zirconium ammonium carbonate gel produced by: bringing a zirconium ammonium carbonate sol into contact with a dehydration solvent selected from the group consisting of a dialkyl ketone wherein each alkyl group has 1-3 carbons and a lower aliphatic alcohol having 1-5 carbons, the dehydration solvent containing:   (i) a compound of a metal selected from the group consisting of divalent, trivalent, tetravalent and pentavalent metals; or   (ii) boric acid or ammonium borate; or   (iii) boric acid or ammonium borate together with a compound of a metal selected from the group consisting of divalent, trivalent, tetravalent and pentavalent metals;   wherein the divalent metal is Mg, Ca, Ba, Sr, Pb, Ni, Cu, Zn or Mn; the trivalent metal is Y, Al, Fe, Ga, In, Bi, Ce or La; the tetravalent metal is Ti, Sn, Si, Ge or Te; and the pentavalent metal is V, Mo, Sb or W.   
     
     
       8. A zirconium ammonium carbonate gel produced by: (a) reacting a zirconium ammonium carbonate sol with boric acid or ammonium borate, to provide a boratozirconium ammonium carbonate sol; and   (b) bringing the sol into contact with a dehydration solvent selected from the group consisting of a dialkyl ketone wherein each alkyl group has 1-3 carbons and a lower aliphatic alcohol having 1-5 carbons, the dehydration solvent containing:   (i) a compound of a metal selected from the group consisting of divalent, trivalent, tetravalent and pentavalent metals; or   (ii) boric acid or ammonium borate; or   (iii) boric acid or ammonium borate together with a compound of a metal selected from the group consisting of divalent, trivalent, tetravalent and pentavalent metals, wherein the divalent metal is Mg, Ca, Ba, Sr, Pb, Ni, Cu, Zn or Mn; the trivalent metal is Y, Al, Fe, Ga, In, Bi, Ce or La; the tetravalent metal is Ti, Sn, Si, Ge or Te; and the pentavalent metal is V, Mo, Sb or W.